US9056796B2 - ATZ fused grains - Google Patents

ATZ fused grains Download PDF

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Publication number
US9056796B2
US9056796B2 US14/006,824 US201214006824A US9056796B2 US 9056796 B2 US9056796 B2 US 9056796B2 US 201214006824 A US201214006824 A US 201214006824A US 9056796 B2 US9056796 B2 US 9056796B2
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oxides
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US20140011660A1 (en
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Stephane Raffy
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Saint Gobain Centre de Recherche et dEtudes Europeen SAS
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Saint Gobain Centre de Recherche et dEtudes Europeen SAS
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/72—Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80—Phases present in the sintered or melt-cast ceramic products other than the main phase
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C04B2235/9607—Thermal properties, e.g. thermal expansion coefficient

Definitions

  • the invention relates to fused grains based on alumina, titanium oxide and zirconia, to a process for manufacturing such grains, to a sintered product comprising such grains, and to an application in which such a sintered product is intended to come into contact with a molten metal.
  • a ceramic sintered product In order to be able to be used in such an application, a ceramic sintered product must have a good mechanical strength, a good resistance to thermal shocks and a good corrosion resistance in contact with the molten metal.
  • the choice of the grains used for manufacturing the product is, to that end, a determining factor.
  • a slide gate is in particular used in the continuous casting of steel in order to open or close tundishes or discharge orifices of ladles in fluid communication with ingot molds, via a continuous casting nozzle or sliding nozzle.
  • the slide gates are obtained by sintering a mixture of corundum and of fused zirconia-mullite grains and optionally fused alumina-zirconia grains.
  • EP 1 820 785 describes a slide gate manufactured by sintering a mixture comprising fused grains having between 10% and 50% of alumina Al 2 O 3 , between 10% and 40% of TiO 2 and more than 50% of zirconia, as weight percentages.
  • this objective is achieved by means of a molten grain comprising, for a total of 100%:
  • a fused grain according to the invention may also have one or more of the following features:
  • the invention also relates to a powder comprising, or even consisting of, grains according to the invention and the use of such a powder for the manufacture of a slide gate or of a lining of a furnace, for example an induction furnace, in particular for melting metals.
  • the powder may in particular be of the dry ramming mix or “DVC”, dry vibratable mix or dry refractory, type.
  • a powder of grains according to the invention may have a median diameter (d 50 ) of greater than 2 ⁇ m, greater than 5 ⁇ m, or greater than 10 ⁇ mm or greater than 50 ⁇ m and/or less than 8 mm, less than 7 mm, less than 5 mm, less than 3 mm, less than 2 mm, less than 1 mm, or less than 500 ⁇ m.
  • the invention also relates to a sintered product obtained by sintering a powder according to the invention or a mixture of powders comprising at least one powder according to the invention having different median sizes, in particular in the form of a lining or a slide gate.
  • a sintered product according to the invention has an open porosity of less than 30%, less than 20%, or less than 15%.
  • the invention also relates to a process for manufacturing a powder of fused grains according to the invention, comprising the following successive steps:
  • the raw materials are chosen in step a) so that the solid mass obtained at the end of step c) has a composition in accordance with that of a grain according to the invention.
  • the invention finally relates to the use of a sintered product according to the invention or obtained according to a process in accordance with the invention, in an application in which it is subjected to a thermal shock and/or in which it is in contact with a molten metal, in particular in the form of a lining or a slide gate.
  • it relates to an installation chosen from a furnace and a slide gate comprising a sintered product obtained by sintering a powder of grains according to the invention, in particular in a region where said sintered product is intended to be in contact with a molten metal.
  • Fused grains according to the invention may be manufactured according to the aforementioned steps a) to d).
  • step a raw materials are conventionally measured out so as to obtain the desired composition, then mixed in order to form the feedstock.
  • Titanium may be introduced in any form, in particular in the form of an oxide TiO 2 or in metallic form or in the form of a zirconia-titanium oxide alloy, or of alumina titanate.
  • the alkali metal oxides and alkaline-earth metal oxides are impurities.
  • the content of impurities is less than 3%, less than 2%, less than 1%, or less than 0.5%.
  • step b) use is preferably made of an electric arc furnace, but all known furnaces can be envisaged, such as an induction furnace or a plasma furnace, provided that they make it possible to completely melt the feedstock.
  • the firing is preferably carried out under neutral conditions, for example under argon, or oxidizing conditions, preferably at atmospheric pressure.
  • the cooling may be rapid, i.e. so that the molten material is completely solidified in less than 3 minutes.
  • the cooling may result from a casting into CS molds as described in U.S. Pat. No. 3,993,119 or from a quenching. It may also be slow (ingot cooled in the open air or annealing block).
  • step c) does not make it possible to obtain a powder of grains, or if these grains do not have a suitable particle size for the intended application, milling (step d)) may be carried out, according to conventional techniques.
  • the manufacture of a sintered product according to the invention, from a powder of grains according to the invention, may be carried out by any known process.
  • the raw materials were measured out and mixed in order to form a feedstock of appropriate composition.
  • the feedstock was pressed in order to form a preform in the form of a disk having a diameter of 13 mm and a height of 13 mm.
  • the feedstock was melted in an electric arc furnace, in air, under oxidizing electrical conditions, then cooled.
  • the solid masses obtained were then milled and screened in order to obtain powders having a median diameter (d 50 ) between 10 and 15 ⁇ m.
  • the powders of fused grains were pressed in order to form preforms in the form of disks, similar to that of example 3.
  • the chemical composition indicated as weight percentages on the basis of the oxides, was determined by X-ray fluorescence.
  • the porosity (P) was determined conventionally by measuring the geometric density and absolute density determined, on the milled sample, by helium pycnometry.
  • the expansion coefficient “a” was measured between 50° C. and 600° C.
  • the compressive strength “b” was determined at ambient temperature, in a conventional manner, on samples 1 to 4.
  • Table 1 indicates that the grains according to the invention (example 2) result in a sintered product that has a particularly high mechanical strength.
  • example 2 shows the advantage of grains obtained by melting, referred to as “fused” grains. This is because the melting of the feedstock results in a better mechanical strength and a lower porosity, making it possible to limit the corrosion and/or the infiltration.
  • Table 1 shows that the grains according to invention have an expansion coefficient “a” that is lower than that of example 4* or than that of fused mullite-zirconia grains (of the order of 7 ⁇ 10 ⁇ 6 ° C. ⁇ 1 ) or than that of fused alumina-zirconia grains (of the order of 10 ⁇ 10 ⁇ 6 ° C. ⁇ 1 ). This makes it possible to obtain products having a better resistance to thermal shocks.
  • the crystalline phases present in the sample of example 2 were characterized by X-ray diffraction.
  • a silicate phase and another phase essentially consisting of titanium oxide and zirconia.
  • the stability of the crystalline phases present was verified by a test consisting in comparing, by X-ray diffraction, the crystalline phases initially present in the sample of example 2 to those present in this same sample after a heat treatment of 100 hours at 800° C.
  • the invention provides a grain suitable for being effectively used in a sintered product intended to be in contact with a molten metal.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Composite Materials (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Thermal Sciences (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)
  • Catalysts (AREA)
US14/006,824 2011-03-31 2012-03-27 ATZ fused grains Expired - Fee Related US9056796B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR1152725A FR2973368B1 (fr) 2011-03-31 2011-03-31 Grains fondus atz
FR1152725 2011-03-31
PCT/IB2012/051461 WO2012131582A1 (fr) 2011-03-31 2012-03-27 Grains fondus atz

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US20140011660A1 US20140011660A1 (en) 2014-01-09
US9056796B2 true US9056796B2 (en) 2015-06-16

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EP (1) EP2691349B1 (ja)
JP (1) JP5745158B2 (ja)
CN (1) CN103459349B (ja)
FR (1) FR2973368B1 (ja)
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WO (1) WO2012131582A1 (ja)

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CN108046772A (zh) * 2017-12-20 2018-05-18 山东磊宝锆业科技股份有限公司 电熔氧化铝/氧化钛复合材料的生产方法
CN110563472A (zh) * 2019-09-23 2019-12-13 郑州德众刚玉材料有限公司 一种适用于全氧燃烧玻璃熔窑用电熔锆刚玉砖及其生产工艺

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EP1820785A1 (fr) 2006-02-17 2007-08-22 Saint-Gobain Centre de Recherches et d'Etudes Européen Grain fondu d'alumine - oxyde de titane - zircone
US20080203627A1 (en) 2007-02-27 2008-08-28 Steven Bolaji Ogunwumi Ceramic materials for 4-way and NOx adsorber and method for making same
WO2010001065A2 (fr) 2008-07-04 2010-01-07 Saint-Gobain Centre De Recherches Et D'etudes Europeen GRAINS FONDUS D'OXYDES COMPRENANT AL, TI, MG et ZR ET PRODUITS CERAMIQUES COMPORTANT DE TELS GRAINS
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EP2691349A1 (fr) 2014-02-05
FR2973368A1 (fr) 2012-10-05
HUE034280T2 (en) 2018-02-28
CN103459349A (zh) 2013-12-18
WO2012131582A1 (fr) 2012-10-04
JP5745158B2 (ja) 2015-07-08
EP2691349B1 (fr) 2017-06-07
US20140011660A1 (en) 2014-01-09
FR2973368B1 (fr) 2013-11-08
JP2014514998A (ja) 2014-06-26
CN103459349B (zh) 2016-10-19

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